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2 years ago

Which of the following is a CHEMICAL CHANGE?

Chemistry

1 answer:

mihalych1998 [28]2 years ago

8 0

Answer:

G, but I think that theres more than one answer

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If a temperature increase from 21.0 ∘c to 35.0 ∘c triples the rate constant for a reaction, what is the value of the activation

Airida [17]

Answer:

59.077 kJ/mol.

Explanation:

From Arrhenius law: <em>K = Ae(-Ea/RT)</em>

where, K is the rate constant of the reaction.

A is the Arrhenius factor.

Ea is the activation energy.

R is the general gas constant.

T is the temperature.

At different temperatures:

<em>ln(k₂/k₁) = Ea/R [(T₂-T₁)/(T₁T₂)]</em>

k₂ = 3k₁ , Ea = ??? J/mol, R = 8.314 J/mol.K, T₁ = 294.0 K, T₂ = 308.0 K.

ln(3k₁/k₁) = (Ea / 8.314 J/mol.K) [(308.0 K - 294.0 K) / (294.0 K x 308.0 K)]

∴ ln(3) = 1.859 x 10⁻⁵ Ea

∴ Ea = ln(3) / (1.859 x 10⁻⁵) = 59.077 kJ/mol.

4 0

2 years ago

A sample of the mineral hematite Iron (III) oxide has a mass of 12.4g. How many moles of the mineral are present?

8090 [49]

Thus problem is providing us with the mass of iron (III) oxide as 12.4 g so the moles are required and found to be 0.0776 mol after the calculations:

<h3>Mole-mass relationships:</h3>

In chemistry, we use mole-mass relationships in order to calculate grams from moles and vice versa. In this case, since we are given the mass of iron (III) oxide as 12.4 g one can calculate the moles by firstly quantifying its molar mass:

$Fe_2O_3\rightarrow 2*55.85 g/mol+3*16.00 g/mol=159.7g/mol$

Then, we prepare a conversion factor in order to cancel out the grams and thus, get moles:

$12.4gFe_2O_3*\frac{1molFe_2O_3}{159.7gFe_2O_3} \\\\=0.0776molFe_2O_3$

Learn more about mole-mass relationships: brainly.com/question/18311376

8 0

1 year ago

Aluminum can react with oxygen gas to produce aluminum oxide (Al2O3). What type of reaction is this?

Pachacha [2.7K]

It's Synthesis, single replacement is incorrect.

6 0

3 years ago

Write balanced chemical equations for the sequence of reactions that oxalic acid can undergo when it's dissolved in water.

Mashcka [7]

Answer and Explanation:

The balanced chemical equations are as follows:

The chemical formula of oxalic is $H_2C_2O_4$

In the case when oxalic acts reacted with the water so here the oxalic acid eliminates one proton that leads to the development of mono acids

After that, the second step derives that when oxalic acid is in aqueous solution eliminates other proton so it represent the polyprotic acid

Now the chemical equations are as follows:

Elimination of one proton

$H_2C_2O_4(aq)+H_2O(l) \rightarrow H_2C_2O_4^-(aq) + H_3O^+(aq)$

Now the elimination of other proton

$HC_2O_4^-(aq)+H_2O(l) \rightarrow C_2O_4^2^-(aq) + H_3O^+(aq)$

7 0

2 years ago

Why LED is better option for testing the conduction of electricity?

Anettt [7]

Answer:

Led is a light-emitting diode, a semiconductor diode that glows when a voltage is applied. So, there is always a sure result of whether a substance conducts electricity or not as the light glows. That is why it is a better option for testing conduction of electricity.

Explanation:

5 0

2 years ago